The various "charges" imposed by airlines in the UK, loco, Flybe and legacy, are nothing other than the fare distributed under other names so that the so-called headline fare is as low as possible.
This reflects the airlines' assessment of their customers' intelligence. And perhaps there are still people who believe that the published "fare" is a real figure.
There was never any point in protesting that the "taxes" are, apart from APD, simply various charges made by airports and handing companies to the airline, or that "credit card charges", "booking fees" and so on are 100 times the actual cost, or that "baggage charges" are far higher than the cost of carrying and handling the baggage, or that "printing your boarding card" does not actually cost £60.
It's all the cost of the seat from A to B. Get over it.
Legislating to prevent one of these charges being more that a completely undefinable cost will achieve nothing apart from transferring the charge to a new and equally absurd, imaginary service..
Legislating effectively to put the whole cost up front in the advertising and booking process would achieve a lot in terms of avoiding wasting everyone's times and bandwidth finding out what the whole cost is going to be. South West in Plymouth did just that, and it didn't do them any h.......... Sorry, scrub that.